Vertical engine driven air compressor

ABSTRACT

The invention recites an apparatus comprising an internal combustion engine including an engine housing and a vertical shaft extending out of the engine housing. The engine is operable to rotate the shaft. The apparatus further includes an air compressor having a compressor housing, a drive member, an air intake, and an air outlet. The drive member is connected to the engine shaft and is rotatable in response to rotation of the engine shaft. The air compressor draws in low-pressure air through the air intake and discharges a flow of high-pressure air through the air outlet in response to rotation of the drive member. The apparatus also includes an accumulator tank that receives the flow of high-pressure air from the air outlet.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to air compressors, and particularly to engine driven air compressors. More particularly, the present invention relates to mobile engine driven air compressors.

[0002] Air compressors provide compressed air to operate air-powered tools at many types of facilities including construction sites, automobile repair facilities, and factories to name a few. In addition, air-powered equipment may be used in retail stores for displays or in any facility for maintenance duties. Many air compressors provide air for an entire facility and as such are quite large. These large compressors are permanently installed and powered by an electric motor. A system of accumulator tanks, distribution pipes, and manifolds transport the compressed air to points-of-use throughout the facility.

[0003] In some cases, a large air compressor is unnecessary. For example, home construction may require a compressor able to operate a single air-operated tool. In addition, a construction site may not have electrical power, thereby requiring a compressor driven by an internal combustion engine or other non-electrical prime mover. Furthermore, construction sites do not have elaborate air distribution systems, thus making it necessary to place high-pressure air hoses between the compressor and the desired point-of-use. A mobile compressor would minimize the quantity of hose required, thereby making for a more organized work site.

SUMMARY OF THE PREFERRED EMBODIMENT

[0004] The apparatus of the present invention provides an internal combustion engine including an engine housing and a shaft extending vertically out of the engine housing. The engine is operable to rotate the shaft. The apparatus further includes an air compressor having a compressor housing, a drive member, an air intake, and an air outlet. The drive member connects to the engine shaft along a vertical axis and is rotatable in response to rotation of the engine shaft. The air compressor draws in low-pressure air through the air intake and discharges a flow of high-pressure air through the air outlet in response to rotation of the drive shaft. The apparatus also includes an accumulator tank that receives the flow of high-pressure air from the air outlet.

[0005] In preferred embodiments, the engine is a lawnmower engine including a mounting flange having a standard bolt pattern. The flange facilitates attachment of the engine to the air compressor housing. Of course, other mounting arrangements may be used.

[0006] In another construction, the apparatus provides a frame, a plurality of wheels supporting the frame, and an internal combustion engine supported by the frame. The engine includes an engine housing and a vertical shaft extending out of the engine housing. The engine is operable to rotate the shaft. The apparatus further includes an air compressor supported by the frame, the air compressor having a compressor housing, a drive member, an air intake, and an air outlet. The drive member is connected to the engine shaft and is rotatable in response to rotation of the engine shaft. The air compressor draws in low-pressure air through the air intake and discharges a flow of high-pressure air through the air outlet in response to rotation of the drive member. The apparatus also includes an accumulator tank receiving the flow of high-pressure air from the air outlet.

[0007] The invention also provides a method of assembling a mobile high-pressure air supply apparatus including a frame having a handle and an axle, a plurality of wheels, an internal combustion engine having a vertical drive shaft, an air compressor, and an accumulator tank. The method comprises the steps of attaching the plurality of wheels to the axle, attaching the air compressor to the frame, and providing a drive member connected to the air compressor and engagable with the engine drive shaft. The method also includes the steps of aligning the engine drive shaft vertically with the drive member, engaging the drive member and the engine shaft, attaching the engine to the frame, and attaching the accumulator tank to the frame.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The detailed description particularly refers to the accompanying figures in which:

[0009]FIG. 1 is a perspective view of an apparatus embodying the present invention;

[0010]FIG. 2 is a side view of the apparatus of FIG. 1 partially broken away.

[0011]FIG. 3 is a side view of a portion of the apparatus better illustrating a coupling between the engine and the compressor;

[0012]FIG. 4 is a top view of the portion of the apparatus shown in FIG. 3;

[0013]FIG. 5 is a side view of an alternate construction of an apparatus embodying the present invention partially broken away;

[0014]FIG. 6 is an exploded view of the apparatus of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

[0015] As shown in FIG. 1, an engine driven air compressor unit 10 includes a cart 15, an air compressor 20, an engine 25, a pair of accumulator tanks 30, and various gauges 35, controls 40, and point-of-use connections 45. The cart 15 includes a frame 50 that structurally supports the various components of the compressor unit 10 and defines a central plane A-A. The central plane A-A divides the cart 15 into a front mounting portion 55 and a rear mounting portion 60. The cart 15 also includes a handle portion 65 and a plurality of wheels 70 that allow the cart 15 and the air compressor unit 10 to be mobile. Generally, the cart frame 50 is fabricated from tubular steel or aluminum with any structural material being a suitable substitute so long as it can support the weight of the components. The tubular members connect to one another using any common attachment method with welding being preferred. Other attachment methods include, but are not limited to, bolting, brazing, and soldering. Round or square cross-sectional tubes may be used to fabricate the cart 15, however, other shapes will also function. The frame 50 extends above the engine 25 and air compressor 20 to define the handle portion 65 of the cart 15. The user is able to move the cart 15 onto its wheels 70, and maneuver the cart 15 using the handle portion 65 of the frame 50. In other constructions, separate handle members may extend from the frame 50 to facilitate movement of the cart 15.

[0016] The cart 15 includes two wheels 70, each rotatably attached to an axle. The axle may be a single axle connected to both wheels 70, or may be two distinct axles disposed on a common axis. To move the compressor unit 10, a user applies a force to the handle portion 65 of the frame 50 to pivot the compressor unit 10 onto the wheels 70. The compressor unit 10 is then movable to any desired location. In other constructions, three or more wheels 70 may allow the compressor unit 10 to be moved without having to tip it onto the two wheels 70. Two parallel axles spaced apart from one another support at least three wheels 70 with the compressor unit 10 completely supported by the wheels 70. In still other constructions, a plurality of pivotable castors support the cart 15 for movement as desired.

[0017] The air compressor 20 is supported within a housing 75 that attaches to the cart 15. The air compressor housing 75 substantially encloses the air compressor 20 as well as the piping needed to contain and direct the compressed air. The pipes interconnect a high-pressure air outlet 80 of the compressor 20 (shown in FIGS. 3 and 5) and the inlet of the accumulator 30. In addition, many constructions include a pressure switch or a pressure relief valve (not shown) that allows the user to select the desired storage pressure of the high-pressure air within the accumulator 30. Pipes also extend from the accumulator 30 to various point-of-use connections 45 where the air is discharged and used. In addition, various tubes and pipes may extend from the accumulator 30 or the compressor 20 to instrumentation or controls to provide the user with information and allow for the control of the compressor unit 10. For example, a tube may extend from the accumulator 30 to a pressure gauge 35, thereby allowing the user to visually check the pressure within the accumulator 30. A large portion of these tubes and pipes are substantially contained within the housing 75. Because the location and use of tubes and pipes to convey air are well known, the pipes and tubes have been omitted from the figures to improve clarity.

[0018] In addition to containing and protecting the various pipes and tubes, the housing 75 also functions as a base to support the engine 25. A bolt pattern 85 (best shown in FIG. 6) drilled or otherwise formed into the housing 75 allows for direct connection of the engine 25 to the housing 75. By using a standard bolt pattern 85 (e.g., ANSI, SAE, or ISO standard flange patterns), many different engines 25 can easily attach to the housing 75 and drive the compressor 20. Alternatively, the housing includes a bolt pattern as described in U.S. Pat. No. 5,546,901, assigned to Briggs & Stratton Corporation and herein fully incorporated by reference. Bolts 90 extend through an engine flange 95 and thread into the housing 75 or pass through the housing 75 and engage a nut. In another construction, the bolts 90 pass through the housing 75 and thread into the engine flange 95 or pass through the engine flange 95 and engage nuts.

[0019]FIG. 2 is a partially broken away section view of one possible air compressor 20. The compressor 20 includes a piston 100 positioned to reciprocate within a cylinder 105 and coupled to a drive member such as a crankshaft 110. The crankshaft 110 or another shaft coupled to the crankshaft 110 extends vertically along a vertical axis 7-7. A coupling member 115 (discussed below) attaches to the end of the crankshaft 110, or is formed as part of the crankshaft 110, to facilitate connection of the air compressor 20 to the engine 25. Rotation of the crankshaft 110 about the vertical axis 7-7 produces a reciprocating motion of the piston 100, which in turn produces a flow of high-pressure air. While a piston-type air compressor 20 is illustrated in FIGS. 2-5, many other types of air compressors (e.g., gear-type, screw-type, centrifugal-type, and axial-type compressors) may function with the invention. The actual type of air compressor employed is of little importance to the invention so long as the air compressor can be driven through a vertically extending shaft.

[0020] The coupling member 115 of FIG. 2 is formed as part of the crankshaft 110 and extends vertically toward the top of the housing 75. The crankshaft 110 includes an opening sized to receive the engine drive shaft 120. In some embodiments, the engine drive shaft 120 and coupling member 115 are splined, thereby allowing them engage one another and transmit rotational movement, while still allowing for relative vertical movement. In a preferred embodiment, the engine drive shaft 120 and the coupling member 115 are threaded. Rotation of the engine drive shaft 120 threads the drive shaft 120 into the coupling member 115.

[0021] FIGS. 3-5 illustrate another construction of the air compressor employing a drive member including a separate offset-plate drive 125 rather than a crankshaft 110 and integral coupling member 115. The offset-plate drive 125 includes a collar portion 130 and a plate portion 135. The collar portion 130 can attach to the plate portion 135 or they can be manufactured as one contiguous piece. The collar portion 130 attaches to the engine drive shaft 120 such that rotation of the engine shaft 120 rotates the offset-plate drive 125 about the vertical axis 7-7. The collar portion 130 of FIG. 3 is generally a short hollow tube having an internal bore threaded to receive the drive shaft 120 that extends from the engine 25. The drive shaft 120 threads into the internal bore of the collar portion 130 to couple the compressor and the engine. In other constructions (not shown), the collar portion 130 is part of the engine drive shaft 120, while the offset-plate drive 125 includes a threaded bar portion extending vertically along axis 7-7 and sized to fit within the collar.

[0022] The plate portion 135 includes a connection point 145 that is spaced a distance from the vertical axis 7-7. A connecting rod 150 connects at a first end to the piston 100 and at a second end to the connection point 145 on the plate portion 135. Rotation of the plate 135 results in the connection point 145 and the second end of the connecting rod 150 moving in a circular path around the vertical axis 7-7. This orbital motion produces the desired reciprocating motion at the piston 100. In another construction (not shown), the plate 135 is a bar having a first end and a second end. The collar 130 attaches to the first end of the bar, while the connection point 145 is disposed near the second end of the bar. Engine operation rotates the second end of the bar about the first end, thereby producing the desired reciprocating motion of the piston 100. The actual shape of the plate 135 is not critical to the invention, so long as it provides a connection point 145 to connect the connecting rod 150 so that it is offset from the vertical axis 7-7.

[0023] The connecting rod 150 pivotally connects to the connection point 145 to allow relative movement between the connecting rod 150 and the plate 135. FIG. 4 illustrates one possible way of facilitating relative movement between the connecting rod 150 and the plate 135, wherein the connecting rod 150 includes a bearing 155 that allows for its free rotation about a pin 160. The pin 160 can be a pin, or a bolt threaded into the plate 135 and sized to receive the bearing 155.

[0024] Many internal combustion engines can be adapted to drive a compressor 20. For example, a common lawnmower engine includes a shaft extending vertically and can be connected to the housing 75 to drive the air compressor 20. The engine 25, as shown in FIG. 5, includes an engine housing 163 and the engine flange 95 that attaches to the compressor housing 75 and supports the engine 25, although other mounting arrangements may be used. The engine housing 163 at least partially encloses the moving parts of the engine. In addition, the engine housing 163 provides an opening through which the engine drive shaft 120 extends. The engine 25 includes the drive shaft 120 that extends vertically out of the engine 25. The flange 95 includes a bolt pattern 157 that matches the pattern 85 in the housing 75.

[0025] The invention has been described and illustrated with the air compressor 20 disposed below the internal combustion engine 25. Alternatively, the engine 25 could be positioned below the air compressor 20. In this alternative arrangement, the engine drive shaft 120 extends vertically up to engage the air compressor 20.

[0026] The construction illustrated in FIGS. 1 and 6 includes two accumulator tanks 30 supported by the cart 15 and disposed in the rear mounting portion 60. Tanks 30 are positioned on the opposite side of plane A-A from engine 25, as shown in FIG. 1. Positioning the tanks 30 in the rear mounting portion 60 allows the weight of the tanks 30 to partially offset the weight of the air compressor 20 and the internal combustion engine 25. By partially balancing the weight on either side of the rear wheels 70, the cart 15 becomes easier to pivot onto the wheels 70 when movement is desired.

[0027] The accumulator tanks 30 receive the flow of compressed air from the air compressor 20 and provide a flow of compressed air to the point-of-use connections 45 for use. Accumulator tanks 30 allow for the storage of compressed air, thereby reducing pressure variations of the air at the point-of-use. In addition, the use of accumulators 30 allows the compressor 20 to cycle less frequently, thereby reducing starts and stops and improving component life.

[0028]FIGS. 1 and 2 illustrate two elongated tanks 30 oriented with their longitudinal axis being substantially parallel to axis 7-7. In other constructions, a single larger tank is employed. The actual configuration of the tank is unimportant to the function of the invention. The quantity and orientation of the tanks can very greatly, however, the internal volume of the tanks and the tank construction should be sufficient to contain the desired volume of air at the desired air pressure.

[0029] In operation, the engine rotates the drive shaft 120, which in turn rotates the coupling 125 about the vertical axis 7-7, thereby producing the desired reciprocating motion of the piston 100. As the piston 100 retracts within the cylinder 105, a partial vacuum is produced. The vacuum allows an inlet reed valve 165 to open and admit air. As engine rotation continues, the piston 100 reverses and moves towards the closed end of the cylinder 105. The enclosed volume within the cylinder 105 decreases and the air pressure increases, thereby forcing an outlet reed valve 170 open and the inlet reed valve 165 closed. The high-pressure air flows out a pipe (not shown) to the point-of-use connections 45 and to the accumulator 30. When the air pressure reaches the desired pressure, the engine 25 shuts off, or alternatively a relief valve (not shown) opens allowing the engine 25 to idle without compressing air. While simple reed valves 165, 170 have been described, one-way check valves, solenoid-operated valves, or pressure control valves could also be used to control the flow of air into and out of the compressor cylinder 105. In addition, the invention has been described in terms of a single cylinder 105 acting as a compressor 20. However, the invention should not be limited to single-cylinder compressors, as it will function equally well with multi-cylinder compressors.

[0030] Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims. 

What is claimed is:
 1. An apparatus comprising: an internal combustion engine including an engine housing and a shaft extending vertically out of the engine housing, the engine operable to rotate the shaft; an air compressor having a compressor housing, a drive member, an air intake, and an air outlet, the drive member connected to the engine shaft along a vertical axis and rotatable in response to rotation of the engine shaft, the air compressor drawing in low-pressure air through the air intake and discharging a flow of high-pressure air through the air outlet in response to rotation of the drive shaft; and an accumulator tank receiving the flow of high-pressure air from the air outlet.
 2. The apparatus of claim 1, wherein one of the engine shaft and the drive member further comprises a collar portion, the collar portion sized to engage the other of the engine shaft and the drive member.
 3. The apparatus of claim 1, further comprising a frame having a handle, and a plurality of wheels supporting the frame, the frame supporting the engine, the air compressor, and the accumulator tank.
 4. The apparatus of claim 3, wherein the frame defines a first side and a second side, and wherein the engine and the air compressor are disposed on the first side of the frame and the accumulator tank is disposed on the second side.
 5. The apparatus of claim 3, wherein the engine further comprises a mounting flange including a first standard bolt pattern, and the compressor housing further includes a second standard bolt pattern, the first and second bolt patterns being substantially similar to facilitate attachment of the engine to the compressor housing.
 6. The apparatus of claim 1, wherein the internal combustion engine is a lawnmower engine.
 7. The apparatus of claim 1, further comprising a valve adjustable to a relief pressure, wherein the valve opens to discharge air from the accumulator tank in response to pressure within the tank above the relief pressure.
 8. The apparatus of claim 1, wherein the compressor drive member is a crankshaft and the air compressor is a piston-type compressor having a piston coupled to the crankshaft, the piston reciprocating in response to rotation of the engine shaft.
 9. The apparatus of claim 1, wherein the drive member includes an eccentric coupling including a collar portion, a plate portion, and a connecting point, the collar portion attached to the plate portion and sized to engage the engine shaft, the connecting point spaced a distance from the collar such that rotation of the engine rotates the coupling and the connecting point rotates along a circular path around the collar.
 10. The apparatus of claim 9, wherein the air compressor includes a piston disposed within a cylinder, the piston connected to the connecting point such that rotation of the engine produces a reciprocating motion at the piston.
 11. An apparatus comprising: a frame; a plurality of wheels supporting the frame; an internal combustion engine supported by the frame, the engine including an engine housing and a vertical shaft extending out of the engine housing, the engine operable to rotate the shaft; an air compressor supported by the frame, the air compressor having a compressor housing, a drive member, an air intake, and an air outlet, the drive member connected to the engine shaft and rotatable in response to rotation of the engine shaft, the air compressor drawing in low-pressure air through the air intake and discharging a flow of high-pressure air through the air outlet in response to rotation of the drive member; and an accumulator tank receiving the flow of high-pressure air from the air outlet.
 12. The apparatus of claim 11, wherein one of the engine shaft and the drive member further comprises a collar portion, the collar portion sized to engage the opposite of the engine shaft and the drive member.
 13. The apparatus of claim 11, wherein the accumulator tank is a first accumulator tank and the apparatus further comprises a second accumulator tank.
 14. The apparatus of claim 13, wherein the frame defines a first side and a second side, and wherein the engine and the air compressor are disposed on the first side of the frame and the first and second accumulator tanks are disposed on the second side.
 15. The apparatus of claim 11, wherein the engine further comprises a mounting flange including a first standard bolt pattern, and the compressor housing further includes a second standard bolt pattern, the first and second bolt patterns being substantially similar to facilitate attachment of the engine to the compressor housing.
 16. The apparatus of claim 11, wherein the internal combustion engine is a lawnmower engine.
 17. The apparatus of claim 11, wherein the drive member is a crankshaft and the air compressor is a piston-type compressor having a piston connected to the crankshaft, the piston reciprocating in response to rotation of the engine shaft.
 18. The apparatus of claim 11, wherein the drive member includes an eccentric coupling including a collar portion, a plate portion, and a connecting point, the collar portion attached to the plate portion and sized to engage the engine shaft, the connecting point spaced a distance from the collar such that rotation of the engine rotates the coupling and the connecting point rotates along a circular path around the collar.
 19. The apparatus of claim 18, wherein the air compressor includes a piston disposed within a cylinder, the piston connected to the connecting point such that rotation of the engine produces a reciprocating motion at the piston.
 20. A method of assembling a mobile high-pressure air supply apparatus including a frame having a handle and an axle, a plurality of wheels, an internal combustion engine having a vertical drive shaft, an air compressor, and an accumulator tank, the method comprising the steps of: attaching the plurality of wheels to the axle; attaching the air compressor to the frame; providing a drive member connected to the air compressor and engagable with the engine drive shaft; aligning the engine drive shaft vertically with the drive member; engaging the drive member and the engine shaft; attaching the engine to the frame; and attaching the accumulator tank to the frame. 